One type of fuel pressure regulator valve for a fuel injection system comprises a hollow housing that is divided by a diaphragm assembly into two chambers, one of which is a control chamber and the other of which is a fuel chamber. The fuel chamber has an inlet via which pressurized fuel enters and an outlet via which excess fuel returns to tank. The diaphragm assembly carries a valve element that coacts with a valve seat disposed in communication with the fuel return outlet. The control chamber houses a helical spring which biases the diaphragm assembly, with the attached valve element, toward the valve seat to thereby establish the regulation pressure. The control chamber has a vacuum port via which it communicates with a variable vacuum source, typically engine intake manifold vacuum, so as to keep the pressure drop across the fuel injectors fairly insensitive to changes in intake manifold vacuum.
One example of a fuel pressure regulator of this known type is described in U.S. Pat. No. 4,928,729, which is owned by the assignee of the present invention. The disclosure of U.S. Pat. No. 4,928,729 is incorporated herein by reference. Another known fuel pressure regulating device is described in U.S. Pat. No. 4,729,360.
U.S. Pat. Nos. 4,649,884 and 4,653,528 relate to fuel pressure pulsation absorbers and dampers. In U.S. Pat. No. 4,649,884, a fuel rail has a flexible metal membrane disposed therein to absorb pulsations. While that fuel rail design does act to minimize fuel pulsations to a certain extent, it still requires a fuel pressure regulator which is separate and independent from the membrane. The patent does disclose a plurality of cylindrical sockets which sealedly receive fuel injectors therein.
Fuel injection systems which utilize only a single fuel injector are known and have been used in connection with throttle body injection (TBI) systems. While a TBI system also utilizes a fuel pressure regulator to control pressure of fuel supplied to the injector, the fuel pressure regulator is typically remote from the fuel injector.
Many types of electromechanical operated fuel injectors are known and are commercially available. One illustrative type is a top-feed, solenoid-actuated fuel injector described in commonly assigned U.S. Pat. No. 4,971,254.
In engines that are small and/or have only a small number of cylinders, space is at a premium. The present invention arises in connection with adapting a fuel injection system to small, one and two cylinder engines.
The present invention relates to a combination fuel pressure regulator and fuel injector and generally comprises:
a housing having a hollow interior divided into a fuel chamber and a control chamber by a pressure regulating diaphragm that carries a valve element; PA1 an inlet via which pressurized fuel is delivered to the fuel chamber; PA1 a valve seat disposed within the fuel chamber for coaction with the diaphragm-carried valve element and leading to an outlet via which excess fuel is returned from the fuel chamber to tank; PA1 a spring that biases the diaphragm and valve element toward the valve seat for establishing the regulation pressure; PA1 an injector-receiving socket mounted directly on the cylindrical sidewall of the housing so that the fuel chamber is communicated to the socket in a fluid-tight manner; and PA1 a fuel injector having an inlet received in the socket in a fluid-tight manner and receiving pressurized fuel from the fuel chamber.
For a more complete understanding of the present invention, the reader is referred to the following detailed description, which should be read in conjunction with the accompanying drawings illustrating a preferred embodiment according to the best mode presently contemplated for carrying out the invention. Throughout the following description and in the drawings, like numbers refer to like parts throughout the several views, in which: